"Very strong well made sturdy bolts, 1st combination reset fine, 2nd failed and set it to a number totally way off what I set it to. To fix look at rear of combination wheels and turn each in turn till you see a solid bit of metal in the space under each wheel, the bolt should now be open, the number on the face side should be noted and try resetting again.

Strongly suggest resetting code from factory setting before installing. Could have been costly to replace if hadnt figured out the above myself."